Abdomen - area between the chest and the hips that contains the stomach, small intestine, large intestine, liver, gallbladder, pancreas, and spleen.

Absorption - the way nutrients from food move from the intestines into the cells in the body.

Accessory digestive organs - organs that help with digestion but are not part of the digestive tract. These organs include the tongue, pancreas, liver, gallbladder, and glands in the mouth that make saliva.

Achalasia - a disorder of the esophagus where the muscle at the end of the esophagus does not relax enough to allow food to move properly into the stomach.

Activated charcoal - an over-the-counter product that may help relieve intestinal gas.

Barium - chalky liquid used to coat the inside of organs so that they will show up on an X-ray.

Barium beefsteak meal - during this test, the patient eats a meal containing barium, allowing the radiologist to watch the stomach as it digests the meal. The amount of time it takes for the barium meal to be digested and leave the stomach gives the doctor an idea of how well the stomach is working and helps to detect emptying problems that may not show up on the liquid barium X-ray.

Barium enema (also called lower GI, or gastrointestinal, series) - a procedure that examines the rectum, the large intestine, and the lower part of the small intestine. A fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an X-ray) is given into the rectum as an enema. An X-ray of the abdomen shows strictures (narrowed areas), obstructions (blockages), and other problems.

Belching (also called burping) - noisy release of gas from the stomach through the mouth.

Bernstein test - test to find out if heartburn is caused by acid in the esophagus; involves pouring a mild acid, similar to stomach acid, through a tube placed in the esophagus.

Bezoar - ball of food, mucus, vegetable fiber, hair, or other material that cannot be digested in the stomach, which can cause blockage, ulcers, and bleeding.

Bile - fluid made by the liver and stored in the gallbladder. Bile helps break down fats and gets rid of wastes in the body.

Bile acids - acids made by the liver that work with bile to break down fats.

Bile ducts - tubes that carry bile from the liver to the gallbladder for storage and to the small intestine for use in digestion.

Biliary atresia - condition present from birth in which the bile ducts inside or outside the liver do not have normal openings. Bile becomes trapped in the liver, causing jaundice (yellowing of the skin), and cirrhosis. Without surgery, the condition may cause death.

Biliary stricture - narrowing of the biliary tract from scar tissue. The scar tissue may result from injury, disease, pancreatitis, infection, or gallstones.

Biliary tract (also called biliary system or biliary tree) - consists of the gallbladder and the bile ducts.

Bilirubin - a yellow-green color substance formed when hemoglobin breaks down. Bilirubin gives bile its color. Bilirubin is normally passed in stool. Too much bilirubin in the bloodstream causes jaundice.

Bismuth subsalicylate - nonprescription medication used to treat diarrhea, heartburn, indigestion, and nausea; also part of the treatment for ulcers caused by the bacterium Helicobacter pylori.

Bloating - fullness or swelling in the abdomen that often occurs after meals.

Calculi - stones or solid lumps, typically formed from an accumulation of minerals, such as gallstones.

Campylobacter jejuni - species of bacteria often linked to foodborne illness and diarrhea.

Candidiasis - infection caused by the Candida fungus, which lives naturally in the gastrointestinal tract. Infection occurs when a change in the body, such as surgery, causes the fungus to suddenly overgrow.

Carbohydrates - one of the three main classes of food and a source of energy. Carbohydrates are the sugars and starches found in breads, cereals, dairy products, fruits, and vegetables. During digestion, carbohydrates are changed into a simple sugar called glucose. Glucose is stored in the liver until cells need it for energy.

Cathartics - laxatives.

Catheter - thin, flexible tube that carries fluids into or out of the body.

Cecostomy - tube that goes through the skin into the beginning of the large intestine to remove gas or feces; it is a short-term way to protect part of the colon while it heals after surgery.

Cecum - beginning of the large intestine; it is connected to the lower part of the small intestine, called the ileum.

Celiac disease - a digestive disease that damages the small intestine because of a sensitivity to gluten, which is found in wheat, rye, barley, and oats. This hereditary disorder interferes with the absorption of nutrients from food.

Celiac sprue - another term for celiac disease.

Chlorhydria - too much hydrochloric acid in the stomach.

Cholangiography - series of X-rays of the bile ducts.

Cholangitis - irritated or infected bile ducts.

Cholecystectomy - operation to remove the gallbladder.

Cholecystitis - irritated gallbladder.

Cholecystokinin - hormone released in the small intestine to aid in the digestion of protein and fats.

Choledocholithiasis - gallstones in the bile ducts.

Cholelithiasis - gallstones in the gallbladder.

Cholestasis - blocked bile ducts often caused by gallstones.

Cholesterol - a substance normally made by the body, but also found in foods from animal sources, like beef, eggs, and butter. Too much cholesterol in the body can lead to narrowing and blockage of the arteries, especially those that feed the heart and keep it healthy. High cholesterol can also cause the formation of gallstones. Ideally, blood cholesterol levels should be less than 200mg/dL.

Chronic - referring to a disease or disorder that usually develops slowly and lasts for a long period of time.

Chyme - thick liquid made of partially digested food and stomach juices; made in the stomach and moves into the small intestine for further digestion.

Cirrhosis - a chronic problem makes it hard for the liver to remove toxins (poisonous substances) from the body. Alcohol, medications, and other substances may build up in the bloodstream and cause problems. Cirrhosis is a result of scarring and damage from other diseases, such as biliary atresia and alcoholism.

Clostridium difficile (C. difficile) - bacteria naturally present in the large intestine that make a substance that can cause a serious infection called pseudomembranous colitis, usually in people taking antibiotics.

Colectomy - operation to remove all or part of the colon.

Colic - attacks of abdominal pain, caused by muscle spasms in the intestines.

Colitis - irritation and inflammation of the colon.

Collagenous colitis - type of colitis caused by an abnormal buildup of collagen, a thread-like protein.

Colon - large intestine.

Colonic inertia - condition of the colon when muscles do not work properly, causing constipation.

Colonoscopy - a procedure that allows the doctor to view the entire length of the large intestine, and can often help identify abnormal growths, inflamed tissue, ulcers, and bleeding. It involves inserting a colonoscope, a long, flexible, lighted tube, in through the rectum up into the colon. The colonoscope allows the doctor to see the lining of the colon, remove tissue for further examination, and possibly treat some problems that are discovered.

Colonoscopic polypectomy - removal of tumor-like growths (polyps) using a device inserted through a colonoscope.

Colon polyps - small, fleshy, mushroom-shaped growths in the colon.

Coloproctectomy - proctocolectomy - surgical procedure to remove all or part of the colon and rectum.

Colorectal cancer - cancer that occurs in the colon (large intestine) or the rectum (the end of the large intestine).

Colorectal transit study - a test to show how well food moves through the colon. The patient swallows capsules containing small markers which are visible on X-ray. The patient follows a high-fiber diet during the course of the test, and the movement of the markers through the colon is monitored with abdominal X-rays taken several times three to seven days after the capsule is swallowed.

Colostomy - operation that reroutes the large intestine to a small, external pouch so stool can still leave the body after the rectum has been removed.

Common bile duct - tube that carries bile from the liver to the small intestine.

Common bile duct obstruction - blockage of the common bile duct, often caused by gallstones.

Constipation - condition in which the stool becomes hard and dry.

Continence - ability to hold in a bowel movement or urine.

Continent ileostomy - operation that reroutes the small intestine to an external pouch so stool can exit the body.

Crohn's disease (also called regional enteritis and ileitis) - a chronic form of inflammatory bowel disease that usually affects the lower small intestine (called the ileum) or the colon, but it can affect the entire gastrointestinal tract.

Cryptosporidia - parasite that can cause gastrointestinal infection and diarrhea.

Defecography - an X-ray of the anorectal area that evaluates completeness of stool elimination, identifies anorectal abnormalities, and evaluates rectal muscle contractions and relaxation.

Dehydration - loss of fluids from the body, often caused by diarrhea.

Delayed gastric emptying - or gastroparesis, a condition that leads to slowed passage of food out of the stomach into the small intestine. Problems with gastric emptying can cause nausea, vomiting, and interfere with bowel movements.

Descending colon - part of the colon where stool is stored. Located on the left side of the abdomen.

Diaphragm - muscle wall between the chest and the abdomen. It is the major muscle that the body uses for breathing.

Diarrhea - frequent, loose, and watery bowel movements.

Digestants - medications that aid or stimulate digestion.

Digestion - process the body uses to break down food into simple substances for energy, growth, and cell repair.

Digestive tract - the organs that are involved in digestion, including the mouth, salivary glands, esophagus, stomach, pancreas, liver, gallbladder, small intestine, and large intestine.

Distention - bloating or swelling; usually referring to the abdomen.

Diverticula - plural form of diverticulum.

Diverticulitis - condition that occurs when small pouches in the colon (diverticula) become infected or irritated.

Diverticulosis - condition that occurs when small pouches (diverticula) push outward through weak spots in the colon.

Diverticulum - small pouch in the colon. These pouches are not painful or harmful unless they become infected or irritated.

Dumping syndrome (also called rapid gastric emptying) - condition that occurs when food moves too fast from the stomach into the small intestine.

Duodenal ulcer - ulcer in the lining of the first part of the small intestine (duodenum).

Duodenitis - irritation of the first part of the small intestine (duodenum).

Duodenum - first part of the small intestine.

Dysentery - infectious disease of the colon. Symptoms include bloody, mucus-filled diarrhea, abdominal pain, fever, and loss of fluids from the body.

Dyspepsia - indigestion.

Dysphagia - difficulty swallowing food or liquid, usually caused by blockage or injury to the esophagus.

Electrocoagulation - procedure that uses an electrical current passed through an endoscope to stop bleeding in the digestive tract and to remove affected tissue.

Electrolytes - chemicals such as salts and minerals needed for various functions in the body.

Encopresis - accidental passage of a bowel movement.

Endoscope - small, flexible tube with a light and a lens on the end used to look into the esophagus, stomach, duodenum, colon, or rectum. It can also be used to take tissue from the body for testing or to take color photographs of the inside of the body. Colonoscopes and sigmoidoscopes are types of endoscopes.

Endoscopic retrograde cholangiopancreatography (ERCP) - a procedure that allows the doctor to diagnose and treat problems in the liver, gallbladder, bile ducts, and pancreas. The procedure combines X-rays and the use of an endoscope--a long, flexible, lighted tube. The scope is guided through the patient's mouth and throat, then through the esophagus, stomach, and duodenum. The doctor can examine the inside of these organs and detect any abnormalities. A tube is then passed through the scope, and a dye is injected which will allow the internal organs to appear on an X-ray.

Endoscopic sphincterotomy - procedure often used to remove bile duct stones and to address narrowing or strictures in the common bile duct and/or the pancreatic duct. Also called endoscopic papillotomy.

Endoscopy - procedure that uses an endoscope to diagnose or treat a condition.

Enema - liquid put into the rectum to clear out the bowel.

Enteral nutrition (also called tube feeding) - a way to provide food through a tube placed in the nose, the stomach, or the small intestine. A tube in the nose is called a nasogastric or nasoantral tube. A tube that goes through the skin into the stomach is called a gastrostomy or percutaneous endoscopic gastrostomy (PEG). A tube into the small intestine is called a jejunostomy or percutaneous endoscopic jejunostomy (PEJ) tube.

Enteritis - irritation and inflammation of the small intestine that often leads to diarrhea.

Enteroscopy - examination of the small intestine with an endoscope.

Enterostomy - ostomy, or opening, into the intestine through the abdominal wall.

Erythema nodosum - red, swollen sores that may arise on the lower legs during flare-ups of Crohn's disease and ulcerative colitis.

Esophageal atresia - failure of a baby's esophagus to develop properly so that it ends before reaching the stomach. Food cannot pass from the mouth into the stomach.

Esophageal manometry - this test helps determine the pressure in the esophagus. It is useful in evaluating gastroesophageal reflux and swallowing abnormalities. A small tube is guided into the nostril, then passed into the throat, and finally into the esophagus. The pressure the esophageal muscles produce is then measured.

Esophageal pH monitoring - a test to measure the amount of acid in the esophagus.

Esophageal spasms - muscle cramps in the esophagus that cause pain in the chest.

Esophageal stricture - narrowing of the esophagus often caused by acid flowing back from the stomach.

Esophageal ulcer - sore in the esophagus caused by long-term inflammation or damage from the residue of medications.

Esophageal varices - stretched veins in the esophagus that generally occur due to backflow of blood when the liver is not working properly.

Esophagitis - irritation of the esophagus, usually caused by acid that flows up from the stomach, but can also develop from certain viral and fungal infections.

Esophagogastroduodenoscopy (also called EGD or upper endoscopy) - a procedure that allows the doctor to examine the inside of the esophagus, stomach, and duodenum. A thin, flexible, lighted tube, called an endoscope, is guided into the mouth and throat, then into the esophagus, stomach, and duodenum. The endoscope allows the physician to view the inside of this area of the body, as well as to insert instruments through a scope for the removal of a sample of tissue for biopsy (if necessary).

Familial polyposis - an inherited disease that causes extensive, premature polyps in the colon. These polyps can lead to cancer.

Fatty liver (also called steatosis) - buildup of fat in liver cells.

Fecal fat test - test to measure the body's ability to break down and absorb fat.

Fecal incontinence - being unable to hold stool in the colon and rectum.

Fecal occult blood test - checks for hidden (occult) blood in the stool. It involves placing a very small amount of stool on a special card, which is then tested in the physician's office or sent to a laboratory.

Galactose - a type of sugar in milk products and sugar beets, also produced within the body.

Galactosemia - a buildup of galactose in the body, caused by a lack of one of the enzymes needed to break down galactose into glucose.

Gallbladder - organ that stores the bile made in the liver and sends bile into the small intestine to help digest fat.

Gallstones - solid masses or stones made of cholesterol or bilirubin that form in the gallbladder or bile ducts.

Gardner's syndrome - condition in which many precancerous polyps form throughout the digestive tract.

Gas - air that comes from the normal breakdown of food and is passed out of the body through the rectum (flatus) or the mouth (belch).

Gastrectomy - operation to remove all or part of the stomach.

Gastric - related to the stomach.

Gastric juices - liquids produced in the stomach to help break down food and kill bacteria.

Gastric resection - operation to remove part or all of the stomach.

Gastric ulcer - stomach ulcer.

Gastrin - hormone released after eating, which causes the stomach to produce more acid to aid in digestion.

Gastritis - inflammation of the stomach lining.

Gastrocolic reflex - increase of muscle movement in the gastrointestinal tract when food enters an empty stomach, which may cause the urge to have a bowel movement soon after eating.

Gastroenteritis - infection or irritation of the stomach and intestines, which may be caused by bacteria or parasites from spoiled food or unclean water, or eating food that irritates the stomach lining and emotional upsets such as anger, fear, or stress. It can lead to crampy, abdominal pain, and diarrhea.

Gastroenterologist - doctor who specializes in digestive diseases.

Gastroenterology - field of medicine concerned with the function and disorders of the digestive system.

Gastroesophageal reflux disease (GERD) - a digestive disorder that is caused by the abnormal flow of gastric acid from the stomach into the esophagus.

Gastrointestinal (GI) tract (also called the alimentary canal or digestive tract) - large, muscular tube that extends from the mouth to the anus, where the movement of muscles and release of hormones and enzymes allow food to be digested.

Gastroparesis (also called delayed gastric emptying) - nerve or muscle damage in the stomach that causes impaired emptying of the stomach contents into the small intestine, often leading to vomiting, nausea, or bloating.

Gastrostomy - an artificial opening from the stomach to a hole (stoma) in the abdomen where a feeding tube is inserted.

Gluten - a protein found in wheat, rye, barley, and oats. People who are allergic to gluten often experience irritation and inflammation of the digestive tract when eating products that contain gluten.

Hemorrhoids - swollen blood vessels in and around the anus that cause itching, pain, and sometimes bleeding.

Hepatic - related to the liver.

Hepatitis - inflammation of the liver that sometimes causes permanent damage; caused by viruses, drugs, alcohol, or parasites. There are several different forms of hepatitis:

Hepatitis A - a form of infectious hepatitis caused by the hepatitis A virus. The virus may be spread by fecal-oral contact, fecal-infected food or water, and may also be spread by a blood-borne exposure (which is rare).

Hepatitis B - a form of infectious hepatitis caused by the hepatitis B virus. Transmission of the hepatitis B virus occurs through blood and body fluid exposure such as blood, semen, vaginal secretions, or saliva.

Hepatitis C - a form of infectious hepatitis caused by the hepatitis C virus. Transmission of the hepatitis C virus occurs primarily from contact with infected blood, but can also occur from sexual contact or from an infected mother to her baby.

Hepatitis D - a form of infectious hepatitis caused by the hepatitis (Delta) virus. This form of hepatitis can only occur in the presence of hepatitis B. Transmission of hepatitis D occurs the same way as hepatitis B.

Hepatitis E - a form of infectious hepatitis caused by the hepatitis E virus. This form of hepatitis is similar to hepatitis A. Transmission occurs through fecal-oral contamination. Hepatitis E is most common in poorly developed countries and is rarely seen in the US.

Hepatitis G - the newest form of infectious hepatitis. Transmission is believed to occur through blood and is seen in IV drug users, individuals with clotting disorders, such as hemophilia, and individuals who require hemodialysis for renal failure.

Hepatologist - doctor who specializes in liver diseases.

Hepatology - field of medicine concerned with the functions and disorders of the liver.

Hernia - a protrusion of part of an organ through the muscle that surrounds it.

Hiatal hernia - small opening in the diaphragm that allows the upper part of the stomach to move up into the chest and often causes heartburn.

Hirschsprung's disease - Birth defect in which some nerve cells in the large intestine do not function properly. This leads to impaired muscle movement in the intestine and intestinal blockages.

Hormones - chemical substances created by the body that control numerous body functions.

Hydrochloric acid - acid made in the stomach that works with pepsin and other enzymes to break down proteins.

Ileoanal anastomosis (also called a pull-through operation) - an operation to remove the colon and inner lining of the rectum, but leaving the outer muscle of the rectum intact. The bottom end of the small intestine (ileum) is pulled through the remaining rectum and joined to the anus, allowing stool to pass normally.

Ileoanal reservoir - an operation to remove the colon, upper rectum, and part of the lower rectum. An internal pouch is created from the remaining intestine to hold stool.

Ileocecal valve - a valve that connects the lower part of the small intestine and the upper part of the large intestine (ileum and cecum, respectively). This valve controls the flow of fluid in the intestines and prevents backflow.

Ileocolitis - irritation of the lower part of the small intestine (ileum) and colon.

Ileostomy - operation that makes it possible for stool to leave the body after the colon and rectum are removed in which an opening is made in the abdomen and the bottom of the small intestine (ileum) attaches to it.

Ileum - lower end of the small intestine.

Impaction - trapping of an object in a body passage, such as stones in the bile duct or hardened stool in the colon.

Lactase - an enzyme in the small intestine needed to digest lactose, a sugar found in milk and other dairy products.

Lactase deficiency - lack of an enzyme made by the small intestine called lactase, which prevents the body from digesting lactose (a sugar found in milk and other dairy products) properly.

Lactose - sugar found in milk, which the body breaks down into galactose and glucose.

Lactose intolerance - inability to digest lactose, the sugar in milk, because the body does not produce enough of the lactase enzyme. Symptoms of lactose intolerance include excessive gas, bloating, and diarrhea.

Lactose tolerance test - a test that checks the body's ability to digest lactose (a sugar found in milk and other dairy products).

Laparoscope - a long, thin tube with a camera lens attached that allows the physician to examine the organs inside the abdominal cavity - to check for abnormalities, and to operate through small incisions.

Laparoscopy - a procedure using a laparoscope to look at the inside of the body, and possibly take tissue samples for further tests.

Laparotomy - a surgical incision into a cavity in the abdomen, usually performed using general or regional anesthesia.

Large intestine - part of the intestine that goes from the cecum to the rectum.

Lavage - cleaning of the stomach and colon using a liquid solution and enemas.

Liver - largest organ in the body, which carries out many important functions, such as making bile, changing food into energy, and removing alcohol and poisons from the blood.

Liver enzyme tests (also called liver function tests) - blood tests to determine whether or not the liver and biliary system are irritated or inflamed.

Lower esophageal sphincter - muscle between the esophagus and stomach that helps keep stomach acid from refluxing into the esophagus.

Lower GI (gastrointestinal) series (also called barium enema) - a procedure that examines the rectum, the large intestine, and the lower part of the small intestine. A fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an X-ray) is inserted into the rectum as an enema. An X-ray of the abdomen shows strictures (narrowed areas), obstructions (blockages), and other problems.

Mucus - a thick, jelly-like substance made by the intestines and other organs of the body (such as the nose), that helps coat and protect the lining of the organ. Mucus also helps stool pass through the large intestine and rectum more easily.

Ostomy - operation that makes it possible for stool to leave the body through an opening made in the abdomen; necessary when part or all of the intestines are removed. Colostomy and ileostomy are types of ostomies.

Pancreas - gland that makes enzymes for digestion and the hormone insulin.

Pancreatitis - irritation of the pancreas that can impair its ability to function properly; most often caused by gallstones or alcohol abuse.

Papillary stenosis - condition in which the openings of the bile ducts and pancreatic ducts narrow abnormally.

Parenteral nutrition (also called hyperalimentation or total parenteral nutrition) - a way to provide liquid nutrients directly into a central vein through a special tube in the chest, neck, or arm.

Parietal cells - cells in the stomach wall that make hydrochloric acid.

Pepsin - enzyme made in the stomach that helps to break down proteins.

Peptic - related to the stomach and the duodenum, where pepsin is present.

Peptic ulcer - sore in the lining of the esophagus, stomach, or duodenum; usually caused by the bacterium Helicobacter pylori. An ulcer in the stomach is a gastric ulcer; an ulcer in the duodenum is a duodenal ulcer.

Percutaneous transhepatic cholangiography - X-ray of the gallbladder and bile ducts; a dye is injected through the abdomen to make the organs show up on the X-ray.

Perforated ulcer - ulcer that breaks through the wall of the stomach or duodenum and causes the stomach contents to leak into the abdominal cavity, which can lead to severe bleeding, infection, and inflammation.

Perforation - hole in the wall of an organ.

Perianal - area around the anus.

Perineal - related to the perineum.

Perineum - area between the anus and the sex organs.

Peristalsis - wavelike movement of muscles in the gastrointestinal (GI) tract that moves food and liquid through the GI tract.

Peritoneum - lining of the abdominal cavity.

Peritonitis - infection and inflammation of the peritoneum.

Peutz-Jeghers syndrome - inherited condition in which many polyps grow in the intestine, leading to an increased risk of intestinal cancer.

Pharynx - space behind the mouth that serves as a passage for food from the mouth to the esophagus and for air from the nose and mouth to the larynx.

Polyp - tissue bulging from the surface of an organ.

Polyposis - presence of many polyps.

Porphyria - group of rare, inherited blood disorders in which cells fail to change certain chemical compounds (porphyrins) to the substance (heme) that gives blood its color.

Portal hypertension - high blood pressure in the portal vein, the vein that carries blood into the liver--may often be caused by a blood clot.

Portal vein - large vein that carries nutrient-rich blood from the intestines and spleen to the liver.

Portosystemic shunt - procedure which creates an opening between the portal vein and other veins around the liver in order to help alleviate portal hypertension.

Postcholecystectomy syndrome - condition that may occur after gallbladder removal that causes pain, nausea, and indigestion due to changes in bile flow.

Postgastrectomy syndrome - condition that may occur after an operation to remove all or a portion of the stomach (gastrectomy). It can lead to abdominal pain, nausea, diarrhea and malnutrition.

Postvagotomy stasis - delayed stomach emptying that often occurs after surgery and affects the vagus nerve.

Pouch - special bag worn over a stoma to collect stool, this is sometimes referred to as an ostomy appliance.

Salmonella - bacterium that may cause intestinal infection and diarrhea.

Sarcoidosis - condition that can cause inflammatory changes in the liver, heart, lungs, and spleen.

Sclerotherapy - method of stopping upper GI bleeding. A needle is inserted through an endoscope to deliver medications that help stop bleeding.

Secretin - hormone made in the duodenum that causes the stomach to produce pepsin, the liver to make bile, and the pancreas to produce a digestive enzymes.

Segmentation - process by which muscles in the intestines move food and wastes through the body.

Shigellosis - infection with the bacterium Shigella, usually causing a high fever, bloody diarrhea, and dehydration.

Short bowel syndrome (also called short gut syndrome) - problems related to absorbing nutrients after removal of part of the small intestine.

Shwachman-Diamond syndrome - a rare genetic disorder characterized by pancreatic insufficiency (digestive enzymes are not produced) and low white blood cell count. It also may affect bone growth, lung function and other body systems. It is the second most common cause of pancreatic insufficiency after cystic fibrosis.

Sigmoid colon - lower part of the colon that empties into the rectum.

Sigmoidoscopy - a diagnostic procedure that allows the physician to examine the inside of a portion of the large intestine, and is helpful in identifying the causes of diarrhea, abdominal pain, constipation, abnormal growths, and bleeding. A short, flexible, lighted tube, called a sigmoidoscope, is inserted into the intestine through the rectum. The scope blows air into the intestine to inflate it and make viewing the inside easier.

Small intestine - the section of the digestive tract between the stomach and the large intestine. Most of digestion occurs here as nutrients are absorbed from food.

Somatostatin - hormone in the pancreas that helps tell the body when to make the hormones insulin, glucagon, gastrin, secretin, and renin.

Spasms - muscle movements such as those in the colon that cause pain, cramps, and diarrhea.

Sphincter - ring-like band of muscle that opens and closes an opening in the body.

Sphincter of Oddi - muscle between the common bile duct and pancreatic ducts that regulates the flow of digestive juices and bile.

Spleen - organ that helps to filter the blood and to make white blood cells.

Splenic flexure syndrome - condition that occurs when air or gas collects in the upper parts of the colon.

Steatorrhea - condition in which fat is not properly absorbed by the intestines, leading to the release of fat in the stools.

Stoma - a surgically created opening in an organ, such as the stomach (gastrostomy) or intestine (colostomy).

Stomach - organ between the esophagus and the small intestine. The stomach is where digestion of protein begins.

Stomach ulcer (also called a gastric ulcer) - open sore in the stomach lining.

Tracheoesophageal fistula (TEF) - a congenital (present at birth) or acquired opening between the esophagus and the trachea (the windpipe). It can lead to breathing problems since food can travel from the trachea into the lungs.

Transverse colon - part of the colon that goes across the abdomen from right to left and connects the ascending and descending colon.

Tropical sprue - condition of unknown cause. Abnormalities in the lining of the small intestine prevent the body from absorbing food normally.

Tube feeding (also called enteral nutrition) - a way to provide food through a tube placed in the nose, the stomach, or the small intestine. A tube in the nose is called a nasogastric or nasoantral tube. A tube that goes through the skin into the stomach is called a gastrostomy or percutaneous endoscopic gastrostomy (PEG). A tube into the small intestine is called a jejunostomy or percutaneous endoscopic jejunostomy (PEJ) tube.

Ulcerative colitis - a serious disease that causes ulcers and irritation in the inner lining of the colon and rectum.

Upper GI endoscopy - looking into the esophagus, stomach, and duodenum with an endoscope.

Upper GI (gastrointestinal) series (also called barium swallow) - a diagnostic test that examines the organs of the upper part of the digestive system: the esophagus, stomach, and duodenum (the first section of the small intestine). A fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an X-ray) is swallowed. X-rays are then taken to evaluate the digestive organs.

Vagotomy - operation to cut the vagus nerve, which causes the stomach to produce less acid.

Vagus nerve - nerve with many functions including regulation of the production of stomach acid.

Valve - fold in the lining of an organ that prevents fluid from flowing backward.

Varices - stretched or weakened veins such as those that form in the esophagus due to backflow of blood from cirrhosis.

Video capsule endoscopy - a procedure that helps doctors examine the small intestine, because traditional procedures, such as an upper endoscopy or colonoscopy, cannot reach this part of the bowel. A tiny camera in the shape of a pill is swallowed and takes pictures as it travels through the GI tract. This procedure is helpful in identifying causes of bleeding, detecting polyps, inflammatory bowel disease, ulcers, and tumors of the small intestine.

Villi - tiny, fingerlike projections on the surface of the small intestine that help aid in absorption of nutrients.

Watermelon stomach - parallel red lesions in the stomach that look like the stripes on a watermelon. These lesions arise due to dilation of blood vessels in the stomach. This condition can lead to bleeding and anemia.

Zenker's diverticulum - outpouching of tissue from the esophagus due to increased pressure in and around the esophagus.

Zollinger-Ellison syndrome - group of symptoms that occur when a tumor called a gastrinoma forms in the pancreas. The tumor releases large amounts of the hormone gastrin, which causes too much acid in the duodenum, resulting in ulcers, bleeding, and perforation.